COL

COL

excellent Observations and carious Experiments‘elating to this most: copious Subject.

Promiscuous Observations and Experiments aboutColours.

Its oblevvable, that most transparent Bodies^en they are either split, divided, or extendedo ‘hat they have no sensible thickness upon theiroutfaces, exhibit various Colours like those of theRainbow. Thus is it with Muscovy Glass whenfht into exceeding thin pieces, and tine Glalsw ten blown at the Flame of a Lamp into Bubbles** thin or thinner than the finest Paper; and loe fee it is in those Bubbles which Children make*uiv 0 L a . m 'xture of Soap and Water, and thole, , arise from the shaking of almost any Chy-

5th 0y1, or Spirit of Wine inl ° very fine

*? jle found, that one Grain of Cochinealr .° vc< \hrft i n a pretty quantity of Spint ol U-then that Dissolution diluted with Wa-Colo.,r U <i im P arc a Icnsible, though but a faintco.?’ ? <>* Glasses of Water, each of whichCe nCd * Ounces and ' . which amounts to a-the V 15000 times ils own weightAnd this shewsasM n Y 8reat Divisibility of the Parts of Matter

tlu ^ Bodi lhe lnccstine Motion ° f lholamotDr '*

but r, ^' S Micro^\r. seems to think there

' H°o{ ; r

Which, p Original Colours, vi%. Red and Blue,Hfd T 0< h he defines thus:

qJj* on the Retina made by an

^ ar t p r , Con fi u scd Pulse of Light, whosestrongestf,P f eJJion "h an ^ * tS weakest follows. Blue, ani&bt f xol)oT a< ^ e ^ an an< ^ confused Pulse of

p 0 | »t. q v ° ea kffi fart precedes , and its strongest'flours ut of these two he supposes all other, The w . a f oy mixture, &c. arise.

the p oy which a Liquor may suddenlyc To(i v L°'° Ur of another Liquor, or of ano-‘hes e< Mr. Boyle thinks reducible to such as

'^’'luor Y ,^ e Minute Particles of the Adventitious'• .v. themselves into the Pores of

rh U ' W, filing them up either perfectlyw ^Tiq UQr h Joh"means the Light palling thn

will

lhe ‘ 0 £5nan, n «

ttl *u hllinn .... «i.h»r perfectly or inpalling through.. w — be differently refracted from°!J*y filled when the Pores of it were

ll * e lc h Air, or perhaps some more fub-

, l. ^ 1

V>*<F***J ®l‘ er the Colour of a Bodyr I ffom"' frotn chose things which hind red itV. 0l »r, a . „ a ,PP ear ing in its genuine and properln * r y Bod). len ^ ater walhes off the Filth of or-[P s clea r au S ’ an( I other Lix.iviums or Menstru-

‘ ^fetah a y. or scour off the discoloured Rustz, g > v5c.

?^y ^odv^^'?k a comminution of the Parts ofJ*, and J? , ch^t either by really subdividingpBand se Dar a . n B ‘hem Jess, or else by dis-join-'fifeles \vhirl tln i^ Aggregates or Clusters ofR Dontn^ ^lung together before.l; V “lav i,p V° che last way, the Colour of aGoal; ■ an 8 e d by means of a Liquor’s ma-. hef 0r s . Qr Aggregates of federal Particles1. *hi‘ anv n ,Y t0 ° scattered and dispersed toa-er 5 °f P rp _° ? Ur » a “d this way the new Co-ise. 'Plates may be supposed in part to

A

^ Q dy [, v >1“or may also change the Colour of afefen of .l' T catln 8 3nd changing the Site and Po-e rarts of it: Thus bruized Fruits ap-

pear of a different Colour from their Ripe andNatural ones, and several Bodies are of a differentColour when dissolved in a Menstruum from whatthey had before. i

6. The chiefest and most important way of all,as being that which doth contain many otherswithin it, is by associating the Saline Corpusclesor any other fort of the more rigid ones of theLiquor with the Particles of the Body that it isimployed to work upon, and by that means mustneeds alter the Figure, Position, Bigness, and De-gree of Motion of the Component Particles ofthat Body.

The Learned Dr. Grew thus fumms up the Re-sult of abundance of curious Experiments aboutthe Causes of Vegetable Colours.

1. While the Sulphur and Saline Principles ofPlants do only swim together,and are not yet uni-ted into one Precipitate, no Colour results fromthem, but the Contents are rather Limpid ; asusually in the Boots and many other parenchymouiParts.

Z. But when they are united, and the Alkalinesare predominant, they produce a Green Colour. ■

3. When the Sulphur and Alkaline arc moreequal they make a Tawny.

4. When the Sulphur, Acid, and Alkaline arenearly equal; they produce a Yellow.

5. When the Sulphur is predominant and theAcid and Alkaline equal, it makes a Blue. But,

6. When the Sulphur and Add are predomi-nant to the Alkaline, it produces a Purple.

7. When the Sulphur is predominant to the Al-kaline Principle, and the Acid to them both, itproduces a Scarlet .- But,

L. When the Acid is predominant to the Alka-line, and the Sulphur to them both, a Blood-Bcd $which is the highest and most Sulphureous Colourin Nature, Anatom. of Plants, p. 276, 2,77.

Experiments of the sudden change of Colours.

i. Into a strong Solution of Sublimate in com-mon Water (the Quantity a Spoonful or two)drop 5 or 6 Drops of good Spirit of Urine (or al-most any Volatile Spirit) and the Mixture willpresently appear White; which Whiteness mayimmediately be destroyed by pouring in a littlegood Aqua Fortss. The Tribe of Utinous Saltsare distinguished by producing this white Colour.

a. Drop a large Drop of Syrup of Violets onWhite Paper, it will spread and exhibit a tolera-ble Blue Colour ; then if you drop upon ir anyAcid Spirit or Stygian Liquor, as suppose a dropof Spirit of Vitriol, ’twill immediately turn intoa fine Red ; whereas a drop of Spirit of Urineor any Volatile Spirit would have turned into alovely Green ; as also will a drop of the Solutionof Copper in Spirit of Urine, though it be of adeep Blue it self. Note, To make the Experimentappear the better, ’tis best to stir about or minglethe Liquors with the Tip of your Finger.

3. The Essential Oyl of Annifeeds in cold Wea-ther coagulates and turns Whitish, yet if on thisWhitish Oynrment, spread on White Paper, youlet fall but a drop or two of good Oyl of Vitriol,a Heat and Smoak will arise, and a Blood-redColour will be produced.

4. The Adiaphorous Spirit of Box mingled^vicha Solution of Mercury in Aqua Fortis, made firsta deep Yellow, and then in a Minute or twoturned as deeply Bed; and being digested a Dayor two, let fall a white Precipitate. Mr. Boyle.

5. An